Modern vehicles comprise an increasing number of safety features and automated systems for reducing the risk of accidents. Examples of such features and systems are parking sensors, blind spot monitors, lane keeping systems, systems for automatic cruise control with distance keeping, automated steering systems etc.
Along with the increasing number of fully- or semi-automated systems comes more strict requirements relating to the reliability of such systems. In particular, it is crucial that the systems cannot malfunction or misinform the driver so that the risk of an accident is increased.
Many such systems utilize radar technology for detecting objects in the vicinity of the vehicle, such as other vehicles. However, vehicles are often operated in environments where a radar system provides a large number of echoes making important to be able to detect only the relevant features surrounding the vehicle. Therefore, it is important to reduce the amount of noise, disturbances and spurious echo signals reaching the radar receiver.
Accordingly, it is desirable to provide radar systems which are more reliable and which are not as sensitive to irrelevant and disturbing radar echoes.
US2014/0070982 relates to a vehicle obstacle detection device comprising a radar unit. The radar unit is arranged on a bumper of a vehicle and it has been observed that signals emitted by the radar unit can be reflected in the bumper towards a wheel of the vehicle, where it is reflected back towards the radar unit where it may be misdetected as a target vehicle. US2014/0070982 addresses this problem by suggesting various ways for reducing the reflected echo by arranging a misdetection prevention member between the wheel and the radar unit. The misdetection prevention member may for example comprise a radio wave absorbing material.
However, the above problem and solution only address one of many sources for unwanted echo signals, and there is still a need to further reduce the amount of unwanted echo signals reaching the radar receiver.